Liver fibrosis is characterized by the excessive accumulation of extracellular matrix proteins, which can lead to cirrhosis and liver cancer. Metabolic dysfunction-associated steatosis liver diseases are common causes of liver fibrosis, sharing a similar pathogenesis with carbon tetrachloride (CCl₄) exposure. This process involves the activation of hepatic stellate cells (HSCs) into myofibroblasts. However, the detailed mechanism and effective treatment strategies require further investigation. In this study, we uncovered a negative correlation between VDR expression and YAP within HSCs. Subsequently, we demonstrated that VDR exerted a downregulatory influence on YAP transcriptional activity in HSCs. Intriguingly, activation VDR effectively inhibited the culture induced activation of primary HSCs by suppressing the transcriptional activity of early YAP. Furthermore, in vivo results manifested that hepatic-specific deletion of YAP/TAZ ameliorates CCl4-induced liver fibrosis, and nullified the antifibrotic efficacy of VDR. Importantly, a YAP inhibitor rescued the exacerbation of liver fibrosis induced by hepatic-specific VDR knockout. Moreover, the combined pharmacological of VDR agonist and YAP inhibitor demonstrated a synergistic effect in diminishing CCl4-induced liver fibrosis, primary HSCs activation and hepatic injury in vivo. These effects were underpinned by their collective ability to inhibit HSC activation through AMPK activation, consequently curbing ATP synthesis and HSCs proliferation. In conclusion, our results not only revealed the inhibition of VDR on YAP-activated liver stellate cells but also identified a synergistic effect of VDR agonist and YAP inhibitor in an AMPKα-dependent manner, providing a practical foundation for integration of multi-targeted drugs in the therapy of CCl4-induced hepatic fibrosis.

UNASSIGNED: Schistosomiasis is a zoonotic parasitic disorder induced by the infestation of schistosomes, a genus of trematodes. MicroRNAs (miRNAs) in egg-derived exosomes are crucial for modulating the host\'s immune responses and orchestrating the pathophysiological mechanisms. Although the exosomes secreted by S. japonicum contain abundant miRNAs, the specific roles of these miRNAs in the pathogenesis of schistosomiasis-induced hepatic fibrosis are yet to be comprehensively elucidated. The egg exosomes of S. japonicum secrete miRNA-30, a novel miRNA.
UNASSIGNED: In vitro, the effect of miRNA-30 was evaluated by transfecting HSCs with miRNA mimics. The target gene biosignature for miRNA-30 was predicted using the miRDB software. The effect of miRNA-30 in hepatic fibrosis was evaluated by either elevating its expression in healthy mice or by inhibiting its activity in infected mice by administration of recombinant adeno-associated virus serotype eight vectors expressing miRNA-30 or miRNA sponges.
UNASSIGNED: This novel miRNA can activate hepatic stellate cells (HSCs), the prinary effector cells of hepatic fibrosis, in vitro, i.e., it significantly increases the fibrogenic factors Col1(α1), Col3(α1), and α-SMA at both mRNA and protein levels. In addition, miRNA-30 may activate HSCs by targeting the host RORA gene. In addition, in vivo experiments were conducted by administering a recombinant adeno-associated viral vector to modulate the expression levels of miRNA-30. The overexpression of miRNA-30 in healthy mice significantly elevated the expression of Col1(α1), Col3(α1), and α-SMA at both the transcriptomic and proteomic scales. This overexpression was coupled with a pronounced augmentation in the hepatic hydroxyproline content. Conversely, the in vivo silencing of miRNA-30 in infected mice induced a considerable reduction in the size of hepatic granulomas and areas of collagen deposition. Hence, in vivo, modulation of miRNA-30 expression may play a pivotal role in ameliorating the severity of hepatic fibrosis in mice afflicted with S. japonica.
UNASSIGNED: The study results suggest that miRNA-30 may augment schistosomiasis-induced hepatic fibrosis through a probable interaction with the host RORA. Our study may improve the current theoretical framework regarding cross-species regulation by miRNAs of hepatic fibrosis in schistosomiasis.

The combination of lineage tracing and immunohistochemistry has helped to identify subpopulations and fate of hepatic stellate cells (HSC) in murine liver. HSC are sinusoidal pericytes that act as myofibroblast precursors after liver injury. Single cell RNA sequencing approaches have recently helped to differentiate central and portal HSC. A specific Cre line to lineage trace portal HSC has not yet been described. We used three Cre lines (Lrat-Cre, PDGFRβ-CreERT2 and SMMHC-CreERT2) known to label mesenchymal cells including HSC in combination with a tdTomato-expressing reporter. All three Cre lines labeled populations of HSC as well as smooth muscle cells (SMC). Using the SMMHC-CreERT2, we identified a subtype of HSC in the periportal area of the hepatic lobule (termed zone 1-HSC). We lineage traced tdTomato-expressing zone 1-HSC over 1 year, described fibrotic behavior in two fibrosis models and investigated their possible role during fibrosis. This HSC subtype resides in zone 1 under healthy conditions; however, zonation is disrupted in preclinical models of liver fibrosis (CCl4 and MASH). Zone 1-HSC do not transform into αSMA-expressing myofibroblasts. Rather, they participate in sinusoidal capillarization. We describe a novel subtype of HSC restricted to zone 1 under physiological conditions and its possible function after liver injury. In contrast to the accepted notion, this HSC subtype does not transform into αSMA-positive myofibroblasts; rather, zone 1-HSC adopt properties of capillary pericytes, thereby participating in sinusoidal capillarization.

Hepatic stellate cell (HSC) activation is the essential pathological process of liver fibrosis (LF). The molecular mechanisms regulating HSC activation and LF are incompletely understood. Here, we explored the effect of transcription factor SRY-related high mobility group box 7 (SOX7) on HSC activation and LF, and the underlying molecular mechanism. We found the expression levels of SOX7 were decreased in human and mouse fibrotic livers, particularly at the fibrotic foci. SOX7 was also downregulated in primary activated HSCs and TGF-β1 stimulated LX-2 cells. SOX7 knockdown promoted activation and proliferation of LX-2 cells while inhibiting their apoptosis. On the other hand, overexpression of SOX7 suppressed the activation and proliferation of HSCs. Mechanistically, SOX7 attenuates HSC activation and LF by decreasing the expression of β-catenin and phosphorylation of Smad2 and Smad3 induced by TGF-β1. Furthermore, overexpression of SOX7 using AAV8-SOX7 mouse models ameliorated the extent of LF in response to CCl4 treatment in vivo. Collectively, SOX7 suppressed HSC activation and LF. Targeting SOX7, therefore, could be a potential novel strategy to protect against LF.

Liver fibrosis is a wound-healing process. It can be induced by various chronic liver diseases. Liver fibrosis is characterized by the activation of hepatic stellate cells (HSCs), a key event. However, no effective treatment strategies to cure or alleviate liver fibrosis-induced pathologic changes have yet been developed. Traditional Chinese medicine (TCM) exhibits a good anti-fibrosis action, with few side effects. Gentiana decoction, a TCM also called Longdan Xiegan Tang (LXT), is used for purging the liver in clinical settings. However, the role of LXT in preventing liver fibrosis and the underlying regulatory mechanism have not yet been investigated. This study demonstrates that LXT treatment can protect the liver from the injuries resulting from CCl4-induced liver fibrosis in mice and suppress the activation of HSCs. The mice in the LXT group exhibit litter collagen I and HSC activation marker α-smooth muscle actin (α-SMA) expression. Transcriptome sequencing of the mouse liver tissue reveals that the level of Parkin, a mitophagy marker, decreased in CCl4-induced liver fibrosis. Further study shows that the injection of Parkin-overexpression adeno-associated virus (Parkin-AAV) via the tail vein can reduce CCl4-induced liver fibrogenesis in mice. We conducted a mechanistic study also, which suggests that LXT treatment suppresses the activation of HSCs by upregulating the expression of Parkin. Hence, it can be suggested that LXT inhibits liver fibrosis by activating the Parkin signaling pathway.

BACKGROUND: Liver fibrosis is primarily driven by the activation of hepatic stellate cells (HSCs), which involves various epigenetic modifications.
OBJECTIVE: N6-methyladenosine (m6A), the most prevalent RNA modification in eukaryotic cells, influences numerous physiological and pathological processes. Nevertheless, the role of insulin-like growth factor 2 mRNA-binding protein 3 (IGF2BP3), a reader gene mediating m6A modifications, in liver fibrosis remains unclear.
RESULTS: This study demonstrated that IGF2BP3 knockout reduces liver fibrosis by promoting HSC ferroptosis (FPT) and inactivating HSCs. Multi-omics analysis revealed that HSC-specific IGF2BP3 knockout decreased m6A content in Jagged1 (Jag1), a key component of the Notch signalling pathway. Furthermore, IGF2BP3 deficiency significantly reduced the expression of hairy and enhancer of split-1 (Hes1), a transcription factor in the Notch/Jag1 signalling pathway, with mRNA levels declining to 35%-62% and protein levels to 28%-35%. Additionally, it suppressed glutathione peroxidase 4 (GPX4) (decreased to approximately 31%-38%), a negative regulator of FPT, thereby facilitating HSC FPT progression and reducing profibrotic gene expression.
CONCLUSIONS: These findings uncover a novel IGF2BP3/Notch/Jag1 signalling pathway involving HSC FPT, suggesting promising targets for ameliorating liver fibrosis.
UNASSIGNED: IGF2BP3 deficiency inactivates Jag1 signalling. IGF2BP3 deficiency-mediated m6A modifications promote HSC ferroptosis. IGF2BP3 inhibition facilitates ferroptosis in HSCs via the Hes1/GPX4 axis. IGF2BP3 deficiency inactivates Jag1/Notch1/3/Hes1 signalling pathway inactivation, leading to the decrease in GPX4, which contributes to HSC ferroptosis.

Chronic hepatitis B virus (HBV) infection continues to be a prominent cause of liver fibrosis and end-stage liver disease in China, necessitating the development of effective therapeutic strategies. This study investigated the potential of targeting TGR5 to alleviate liver fibrosis by impeding the activation of hepatic stellate cells (HSCs), which play a pivotal role in fibrotic progression. Using the human hepatic stellate cell line LX-2 overexpressing hepatitis B virus X protein (HBX), this study revealed that TGR5 activation through INT-777 inhibits HBX-induced LX-2 cell activation, thereby ameliorating liver fibrosis, which is associated with the attenuation of mitochondrial fission and introduces a novel regulatory pathway in liver fibrosis. Additional experiments with mitochondrial fission inducers and inhibitors confirm the crucial role of mitochondrial dynamics in TGR5-mediated effects. In vivo studies using TGR5 knockout mice substantiate these findings, demonstrating exacerbated fibrosis in the absence of TGR5 and its alleviation with the mitochondrial fission inhibitor Mdivi-1. Overall, this study provides insights into TGR5-mediated regulation of liver fibrosis through the modulation of mitochondrial fission in HSCs, suggesting potential therapeutic strategies for liver fibrosis intervention.

BACKGROUND: Hepatic fibrosis (HF) is an essential stage in the progression of different chronic liver conditions to cirrhosis and even hepatocellular carcinoma. The activation of hepatic stellate cells (HSCs) plays a crucial role in the progression of HF. IFN- γ/Smad7 pathway can inhibit HSCs activation, while TGF-β1/CUGBP1 pathway can inhibit IFN-γ/Smad7 pathway transduction and promote HSCs activation. Thus, inhibiting the TGF-β1/CUGBP1 pathway and activating the IFN-γ/Smad7 pathway reverses HSCs activation and inhibits HF. Jiawei Taohe Chengqi Decoction (JTCD) was derived from the Taohe Chengqi Tang in the ancient Chinese medical text titled \"Treatise on Febrile Diseases\". We found several anti-HF components in JTCD including ginsenoside Rb1 and others, but the specific mechanism of anti-HF in JTCD is not clear.
OBJECTIVE: To elucidate the specific mechanism by which JTCD reverses HF by inhibiting the activation of HSCs, and to establish a scientific foundation for treating HF with Traditional Chinese medicine (TCM).
METHODS: We constructed a CCl4-induced mice HF model in vivo and activated human hepatic stellate cell line (LX-2) with TGF-β1 in vitro, after which they were treated with JTCD and the corresponding inhibitors. We examined the expression of pivotal molecules in the two pathways mentioned above by immunofluorescence staining, Western blotting and RT-PCR.
RESULTS: JTCD attenuated liver injury and reduced serum ALT and AST levels in mice. In addition, JTCD attenuated CCl4-induced HF by decreasing the expression of α-SMA, COL1A1 and other markers of HSCs activation in mice liver tissue. Moreover, JTCD effectively suppressed the levels of TGF-β1, p-Smad3, p-p38MAPK, p-ATF2, and CUGBP1 in vivo and in vitro and upregulated the levels of IFN-γ, p-STAT1, and Smad7. Mechanically, after using the inhibitors of both pathways in vitro, we found that JTCD inhibited the activation of HSCs by restoring the balance of the TGF-β1/CUGBP1 and IFN-γ/Smad7 pathways.
CONCLUSIONS: We demonstrated that JTCD inhibited HSCs activation and reversed HF by inhibiting the TGF-β1/CUGBP1 signalling pathway and upregulating the IFN-γ/Smad7 signalling pathway. Moreover, we have identified specific links where JTCD interferes with both pathways to inhibit HSCs activation. JTCD is an effective candidate for the clinical treatment of HF.

Activated hepatic stellate cells (aHSCs), the main perpetrators of liver fibrosis, are a promising therapeutic target in the treatment of chronic liver disease. During liver injury, HSCs transcend from a quiescent to a fibrotic phenotype, a process which involves major metabolic reprogramming with altered mitochondrial function. The antiretroviral drug Rilpivirine (RPV) has demonstrated a hepatoprotective and specifically antifibrotic effect in several animal models of chronic liver injury, as well as in vitro. Herein, we use HSCs activated with the profibrogenic cytokine TGF-β to explore whether mitochondrial function is implicated in this effect. The mitochondrial bioenergetic profile, morphology and dynamics of TGF-β-treated cells (48 h) were altered and these effects were prevented by co-treatment with clinically relevant concentrations of RPV. A MitoStress Test (Seahorse Analyzer) revealed that TGF-β increased both oxygen consumption rate (basal respiration, maximal respiration and spare respiratory capacity) and extracellular acidification rate (indicative of increased glycolysis). Cells exposed to TGF-β also displayed diminished mitochondrial membrane potential and enhanced mitochondrial fission. All of these effects were rescued with RPV. RNA sequencing analysis of cells exposed to TGF-β revealed the presence of 338 differentially expressed genes that encode mitochondrial proteins (mito-DEGs), of which 139 and 199 were significantly up- and down-regulated (adjusted p<0.05). This alteration in 15 (10.79 %) and 31 (22.03 %) of the up-regulated and 16 (8.04 %) and 49 (24.62 %) of the down-regulated mitoDEGs was prevented with co-exposure to RPV 4μM or 8μM, respectively. In conclusion, alterations in mitochondrial function are implicated in the antifibrogenic action of RPV, pointing to potential novel antifibrotic targets.

Hepatic stellate cells (HSC) are the source of extracellular matrix (ECM) whose overproduction leads to fibrosis, a condition that impairs liver functions in chronic liver diseases. Understanding the dynamics of HSCs will provide insights needed to develop new therapeutic approaches. Few models of hepatic fibrosis have been proposed, and none of them include the heterogeneity of HSC phenotypes recently highlighted by single-cell RNA sequencing analyses. Here, we developed rule-based models to study HSC dynamics during fibrosis progression and reversion. We used the Kappa graph rewriting language, for which we used tokens and counters to overcome temporal explosion. HSCs are modeled as agents that present seven physiological cellular states and that interact with (TGFβ1) molecules which regulate HSC activation and the secretion of type I collagen, the main component of the ECM. Simulation studies revealed the critical role of the HSC inactivation process during fibrosis progression and reversion. While inactivation allows elimination of activated HSCs during reversion steps, reactivation loops of inactivated HSCs (iHSCs) are required to sustain fibrosis. Furthermore, we demonstrated the model\'s sensitivity to (TGFβ1) parameters, suggesting its adaptability to a variety of pathophysiological conditions for which levels of (TGFβ1) production associated with the inflammatory response differ. Using new experimental data from a mouse model of CCl4-induced liver fibrosis, we validated the predicted ECM dynamics. Our model also predicts the accumulation of iHSCs during chronic liver disease. By analyzing RNA sequencing data from patients with non-alcoholic steatohepatitis (NASH) associated with liver fibrosis, we confirmed this accumulation, identifying iHSCs as novel markers of fibrosis progression. Overall, our study provides the first model of HSC dynamics in chronic liver disease that can be used to explore the regulatory role of iHSCs in liver homeostasis. Moreover, our model can also be generalized to fibroblasts during repair and fibrosis in other tissues.